When a semiconductor wafer (or a semiconductor substrate) on which semiconductor elements are built in is diced into chips, if the surface of the semiconductor wafer is covered by an electrically insulating hard protective film such as oxide film and nitride film, the peeling-off of the protective film is caused in the edge part of a cut line.
With reference to FIG. 1, the protective film 4 provided on the substrate 2 is peeled off during a dicing step by a blade 6. A reference numeral 8 denotes a part of the film peeled off.
In order to prevent the peeling-off of the protective film conventionally, a dicing step is conducted after the protective film is etched away along a dicing line as shown in FIG. 2, reference numeral 10 denoting the part of the protective film etched away.
According to the conventional dicing method in FIG. 2, the step for etching away the protective film is needed to be conducted other than the step for fabricating semiconductor elements, resulting in the problems of the increase of manufacturing steps and cost.
When the semiconductor wafer is diced after the protective film is peeled off along dicing lines, the substrate is laid bare in the edge part of each diced chip. Accordingly, in the case where a semiconductor element 12 is mounted on a printed circuit board 14 and the element 12 is connected to the board 14 through a lead wire 16 as shown in FIG. 3, there is a possibility that the substrate 12 and the wire 16 are electrically shorted around the position 18, resulting in the malfunction of the semiconductor element 12.